Michael carey



M. CAREY.

ENVELOPE. 4

Patented Dec. 25, 1894.

(No Model.) I

Fla-2. v

NITED STATES PATENT OFFICE.

MICHAEL CAREY, OF NEW YORK, N. Y.

ENVELOPE.

SPECIFICATION forming part of Letters Patent No. 531,302, dated December 25, 1894.

Application filed June 5, 1894. Serial No. 613,5605. (No model.)

To all whom it may concern:

Be it known that I, MICHAEL CAREY, of New York city, New York, have invented an Improved Envelope, of which the following is 5 a specification.

This invention relates to. an envelope which is so constructed that any attempt to open the gummed flap by steaming or mcistening will be at once detected.

[0 In the accompanying drawings: Figure 1 is a perspective view of my improved envelope, showing it open. Fig. 2 is a cross section of the same, and Fig. 3 a perspective view of the envelope, showing the efiects of steaming or x 5 moistening.

The letter a, represents an envelope having a gummed flap a, as usual. I secure to the inner face of the flap, a composition or powder b, which is dissoluble by steam or moistzo ure, and which when dissolved, will penetrate and discolor the flap.

The composition which I prefer to use consists of about three parts of powdered soda, one part of extract of logwood and one-half :5 part of copperas.

The composition is applied in a thin layer to the envelope and is confined and protected by a covering a, which consists of a piece of paper having a gummed edge and secured to 0 the envelope over the composition.

and will strike through the body of the flap,

to discolor the outer face of the same, as at d, 3 5 Fig. 3. In this way any attempt to tamper with the envelope, is at once disclosed.

The covering 6, prevents the composition 6, from discoloring the letters contained in the envelope, and it also prevents accidental contact between the tongue and the composition, during the closing of the envelope.

My improved envelope may be used for ordinary correspondence and also .to convey valuable and secret communications.

What I claim is An envelope provided on its inner flap with a powder which is an absorbent of water and soluble therein, and whosesolution is a coloring compound, said powder being secured in place and likewise protected from accidental contact with moisture, by a suitable covering, substantially as described.

MICHAEL CAREY.

Witnesses:

F. v. BRIESEN, WILLIAM ScHULz. 

